German Pat. No. 2,915,538 (corresponding to U.S. Pat. No. 4,357,865) discloses a process for recovering oil from oil fruits and oil seeds by cleaning, cold pressing and extraction; wherein the oil fruits or oil seeds are prepressed cold immediately after cleaning without mechanical and thermal conditioning, and the remaining solids are then extracted. The process is performed in a strainer screw press which includes a rotating screw, a perforated curb around the screw, a strainer constructed of rods, and at least one choke; wherein the curb tapers to become narrower toward the discharge end and each one of the inserted chokes forms a shear gap between itself and the curb, with the relationship between each gap and the respective curb being between 1:3 and 1:15.
The oil fruits and oil seeds which have been prepressed in the strainer screw press are then extracted with a liquid solvent, preferably hexane. It is necessary to remove the solvent from the extracted material in a further process stage, which requires a large amount of energy since the solvent used for the extraction must be separated quantitatively from the extract in the solvent separation stage.